<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    div {
        width: 100px;
        height: 100px;
        background-color: pink;
    }
</style>

<body>
    <script>
        //调整窗口大小：window.onresize

        //实例：当窗口的大小小于800像素的时候隐藏容器
        window.addEventListener('load', function () {
            var div = document.querySelector('div');
            window.addEventListener('resize',function(){
                // console.log(window.innerWidth);
                if(window.innerWidth <= 800){
                    div.style.display = 'none'
                }else{
                    div.style.dispaly = 'block'
                }
            })

        })

    </script>
    <div></div>
</body>

</html>